In this paperback, Ruben L.F. Habito, a Jesuit priest, makes a clear case that Zen practice can help focus one's faith in God. Here is an excerpt on the common themes of self-emptying in both traditions, a process that leads to transformation.

"This koan is an invitation for us to enter this arduous process, the one we venture into every time we sit zazen, composing ourselves by folding our legs and straightening our backs, regulating our breathing, focusing our minds to the point of ripe concentration. We are called to become the disciple, in an earnest search for peace of mind, in this indefatigable striving to get to the bottom of that mind and take possession of it, to experience the unattainable. We are invited to surrender everything, even the search itself! It is there that the revelation of a whole new world, a whole new universe, is waiting for us.

"This invitation is no less than the one extended by Jesus to the rich young man in search of eternal life. 'Go and sell all that you have, give it to the poor, and come, follow me.' (Luke 10:21)

"Jesus thus calls on him to divest himself of all his cherished possessions, let them go, and enter a hitherto totally unknown territory in following the Son of Man — an act of total emptying, prerequisite to the full reception of the eternal life he was seeking. And entering into this realm is like entering through the eye of a needle, whereby all our excess baggage and attachments, false self-images, notions of self-importance, discriminative thoughts, and so forth, are recognized for what they are: hindrances we must cast away in order to attain what we seek.

"To sit in Zen requires we let go of all our cherished possessions centered on the attachment to what we normally call the 'self.' We are called to undercut all the layers of this, to get to its very source and bring it to the Zen teacher, that we may be set at peace. But of course, it is not the teacher that sets us at peace. Rather, it is the very discovery of that unattainable mind, or of mind as unattainable, that is itself the source of peace. Or to switch back to Christian language: Realizing this is eternal life.

"But eternal life is not a mere extension of time that knows no end, or even a state of continued deathlessness. It is, rather, a realm that cuts through all our concepts of time, of birth and death, change and decay. It is a realm in which all our familiar concepts have fallen away, as all of them are limited by their opposites. In this realm such notions as time and eternity, permanence and change, stillness and motion, universality and particularity, lose their force as antithetical pairs. In this realm, all opposites find their convergence, their coincidence, and concepts as such are emptied of content and canceled by their opposites. And such a coincidence (which is no mere coincidence!) is itself not a concept but an event, an experiencing of a realm that waits to be uncovered, as we submit to the process of emptying.

"The new world into which Jesus invites the wealthy young man, which is the Realm of Heaven itself, requires for its entry this total and self-emptying which is at the same time a total self-giving, and an abandonment in trust. ”